Bernie Sanders referenced the Holocaust and condemned Republican candidate Donald Trump’s “anti-Muslim rhetoric and hatred” in a visit to a Washington mosque.WASHINGTON — Just one day after Republican presidential candidates argued on the debate stage over how much the FBI should surveil Islamic houses of worship, Bernie Sanders slipped off his shoes and stepped inside a mosque where Malcolm X once presided.

Sanders, the Democratic presidential hopeful and Vermont senator, participated in a roundtable discussion with Muslim, Christian and Jewish leaders at the Masjid Muhammmed mosque on Wednesday, the Washington Post reported. “We must never forget what happened under the racist ideology of the Nazis, which led to the deaths of millions and millions of people, including family members of mine,” Sanders said at the northwest Washington mosque, which calls itself “the nation’s mosque.” A protester identified by NBC News as a large middle-aged man shouted “Sieg Heil” at the rally Monday evening as another protester was dragged away by security services, NBC reported. The stark juxtaposition is typical of the divergent conversations that have occurred on either side of the partisan divide since the Paris terror attack last month. In a hyper-polarized political environment, the Republican and Democratic presidential campaigns seem to exist in parallel universes on everything from taxes to climate change — but now even perceptions of Muslims have become a partisan issue. A narrow plurality of Republican voters, 48%, hold unfavorable view of Muslims compared to 43% who hold a positive view, according to a new NBC News/Wall Street Journal poll.

Republican primary voters’ picked national security and terrorism as top priority, according to that NBC News poll, followed by the deficit and government spending, then job creation and economic growth, and religious and moral values. As Sanders began his remarks Wednesday afternoon at Masjid Muhammad, a mosque with an imam who is a 30-year Air Force veteran, he made it clear he was more interested in discussing the persecution of American Muslims than terrorism. Invoking atrocities that occurred in Nazi Germany, Rwanda, and Bosnia, he warned that hateful speech and the demonization of minorities can lead to tragic consequences, noting that his own family members were victims of the Holocaust. “There are demagogues out there, people like Donald Trump, who once again are attempting to divide us up in xenophobic and racist ways,” Sanders said. “Do we come together? That is the issue of the moment.” His top rival for the Democratic nomination, Hillary Clinton, struck a similar chord just hours before the GOP debate Tuesday, when she met with Muslim leaders in Minneapolis and said the most important way to combat domestic radicalization was to incorporate the Muslim community. And while none of the candidates quite endorsed Trump’s proposal to ban all non-American Muslims from the country, as debate moderator Wolf Blitzer of CNN said during the discussion, “The conversation tonight is about banning Muslims and surveillance of mosques.” But the candidates in either party, locked in heated primaries, are just reflecting the views of their partisan bases. “Public opinion on ISIS and what you should do about it is so polarized by political party that you’re almost talking to two completely different countries,” said Heather Hurlburt, a former Clinton administration foreign policy official now at the New America Foundation.

Republicans were also more likely to express concern about mass shootings than Democrats, even though liberal gun control advocates are more likely to discuss those types of tragedies. Also entirely missing from the debate were issues of top concern to Democratic voters such as climate change, health care, racial justice, and college tuition costs.